Electron discharge device having a hollow conductor integral with the envelope thereof

ABSTRACT

An electron tube has an integral top cap electrically connected to the anode by means of a pressed-fit spring-like member.

United'States Patent 1191 Young 1 Feb. 4, 1975 [54] ELECTRON DISCHARGE DEVICE HAVING 1,330,935 2/1920 Driver 313/286 A HOLLOW CONDUCTOR INTEGRAL 1,897,761 2/1933 McCullough 313/253 2,191,346 2/1940 Greiner 1. 313/274 WITH THE ENVELOPE THEREOF 2,250,647 7/1941 Miller .1 313/318 [75] Inventor: Richard William Young, Madison, 2,267,450 12/1941 Ekstrand et a1 313/318 NJ 2,677,118 4/1954 Stone 339/144 R 2,838,713 6/1958 Macksoud 313/274 [73] Ass1gnee: RCA Corporatlon, New York, NY.

[22] Filed: Dec. 10, 1973 Primary ExaminerA1fred E. Smith Assistant ExaminerWm. H. Punter [2]] Appl' 423473 Attorney, Agent, or Firm-Glenn H. Bruestle; Irwin M.

Krittman; Joel B. Johnson [52] U.S. C1. 313/318, 339/144 T [51] Int. Cl. H0lj 5/52 [58 Field of Search 313/253, 274, 286, 318; 1 1 ABSTRACT 339/144 144 256 258 TC An electron tube has an integral top cap e1ectrica11y connected to the anode by means of a pressed-fit [5 6] References Cited springlike member UNITED STATES PATENTS 1,158,928 11/1915 Keyes 313/318 2 2 Drawmg F'gures \/IIIIIII III/f1 1 ELECTRON DISCHARGE DEVICE HAVING A HOLLOW CONDUCTOR INTEGRAL WITH THE ENVELOPE THEREOF BACKGROUND OF THE INVENTION This invention relates to a novel electron discharge device and, particularly, to an improved top cap therefor.

Certain types of electron discharge devices, such as horizontal output tubes for color television receivers, are characterized by a top cap structure, whereby external electrical connection to the anode is made at the top, rather than the base, of the device. Typically, the anode lead emerges from the top dome of a glass envelope, to which it is vacuum sealed; and is, in turn, soldered to a cylindrical metal cap, which is itself cemented or glued to the glass dome. External connection to the anode is then made by fitting a connector to the metal cap. Such a structure is shown and described, for example, in US. Pat. No. 3,727,088, issued to W. A. Allgaier on Apr. 10, I973.

Although top caps have been successfully employed in such electron discharge devices for many years, several problems associated with their typical structure have remained unresolved. Foremost among these problems is that of mechanical breakage of the glass at the anode lead-to-dome seal, caused by the loosening of the bond between the metal cap and glass dome, which exposes the seal to various physical hazards. Another source of device failure, as well as construction complexity, is the solder connection between the anode lead and the metal cap, which must withstand high operating temperatures and is also adversely affected by any loosening of the metal cap.

SUMMARY OF THE INVENTION The novel electron discharge device comprises a sealed envelope containing a given electrode, a hollow electrical conductor extending through the envelope and having a closed end external to the envelope and an open end internal thereto, and means extending through the open end of the conductor for electrically connecting the electrode and the conductor. Preferably, the connecting means is attached to the electrode, e.g., anode, and comprises a spring-like member in forced contact with an internal surface of the conductor, e.g., anode cap.

BRIEF DESCRIPTION OF THE DRAWING' FIG. 1 is a partial longitudinal view, partly in axial section, of an example of the novel electron discharge device; and

FIG. 2 is a sectional view, along the line 2-2, of the device of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT An example of the novel electron discharge device is shown in FIG. 1. A horizontal output tube 10 comprises an evacuated envelope 12, generally cylindrical in shape and having a top dome 14. The envelope 12 is made typically of lead-glass tubing having an outer diameter of about 1.5 inches and a wall-thickness of between 30 and 35 mils. Protruding through .the dome 14 is a hollow top cap 16 to which the envelope I2 is sealed, i.e., an "integral" top cap 16. The top cap 16 is generally cylindrical in shape, having a constant diameter except for an indented portion 18 near the capto-envelope seal; and made typically of l2-mil Sealmet HC-4 electrical steel marketed by the Allegheny Ludlum Steel Corporation. The closed end of the top cap 16 is external to the envelope 12, whereas the open end thereof is internal thereto. I

The envelope 12 also contains a conventional cage" assembly 20 comprising a plurality of electrodes, including a plate or anode 22, held in spaced relationship by a pair of insulating spacers, only the upper one 24 of which is shown. The anode 22 includes two tabs or ears" 26, which protrude through the upper spacer 24 and to which are electrically and mechanically connected the opposite ends of a U-shaped conducting support wire 28. Attached to the support wire 28, adjacent each of the opposite legs thereof, are two conventional getters 30 of the flat-disc type.

Also connected, both electrically and mechanically, to the support wire 28 is a resilient connector 32 having an end portion extending into the top cap 16 through the open end thereof. As shown further in FIG. 2, the connector 32, made typically of l5-mil type 430 stainless steel, comprises an end portion from which two longer appendages 34 and 36 extends and are connected to the support wire 28, and two shorter appendages 38 and 40 extends within cap 16. All four appendages 34, 36, 38, and 40 are spring metal strips formed integrally with each other, with the free ends of the strips extending toward the anode 22. The free ends of the strips 34 and 36 are fixed to the support wire 28. The strips bow outwardly and are forced into direct contact with the inner surface of the top cap 16, which serves as a source of electrical connection to the anode 22. External connection to the anode 22 can then be made by fitting a conventional top-cap connector (not shown) to the outer surface of the top cap 16.

The horizontal output tube 10, described above, is typically made as follows. The top cap 16 is sealed to the top dome 14 of a cylindrical lead-glass bulb having an open end at the bottom thereof, using the equipment and techniques commonly employed in sealing a conventional high voltage (typically 20,000-volt) anode assembly thereto. 'That is, the upper portion of a suitable length of lead-glass'tubing is rolled inwardly, by

heating, to form the top dome 14. The top cap 16 is,

brought through the dome 14, by indexing, and then sealed, again by heating.

The cage assembly 20 is separately assembled, with the ears 26 of the anode 22 protruding through the upper spacer 24 thereof, and the ends of the support wire 28 are then welded to the protruding ears 26. Thereafter, the getters 30 and the longer appendages 34 and 36 of the spring-like member 32 are welded to the support wire 28. The electrode tabs or ears protruding through the lower insulating spacer (not shown) of the cage assembly 20 are in turn welded to appropriate ones of the conducting leads or pins of a conventional glass stem assembly (not shown), which includes a glass button" through which the pins extend and an axiallydisposed exhaust tubulation (also not shown).

The interconnected tube assembly comprising the stem assembly, cage assembly 20, support wire 28, getters 30, and connector 32 is next inserted through the bottom of the bulb, such that all four appendages 34, 36, 38, and 40 of the connector 32 are pressed-fit or compressed into the open end of the integral top cap 16 and forced into direct contact with the inner surface thereof. At the other end of the thus-inserted interconnected tube assembly, the outer edge of the stern assembly becomes circumscribed by the inner wall of the bulb. The bulb containing the interconnected tube assembly is then placed on a standard glass sealing lathe or Sealex-type machine, whereby the stem is sealed to the inner wall of the bulb. The device is thereafter evacuated through the exhaust tubulation, and then vacuum sealed thereat, to produce the finished tube 10.

The novel structure of the tube thus permits the separate assembly and testing of the interconnected tube assembly, on one hand, and the top cap-bulb assembly, on the other hand, to reduce manufacturing shrinkage as well as simplify device construction. Mechanical breakage at the top dome 14 of the tube 10 is reduced significantly by its integral vis-a-vis cemented or glued top-cap construction. The embossing associated with the indented portion 18 of the top cap 16 further enhances the ruggedness of the tube 10. Also, the pressed-fit relationship of the resilient connector 32 to the top cap 16 eliminates another source of device failure as well as construction complexity, i.e., the usual solder connection between the conventional anode lead and top cap.

GENEREAL CONSIDERATIONS It should be understood that the invention is not limited to the embodiment described above. For example, the electron discharge device may be other than a horizontal output tube; and the envelope thereof may be made, in part or in whole, of material other than lead glass, e.g., lime glass or ceramic. Furthermore, the shape and material of the top cap may be other than cylindrical and stainless steel, respectively. Also, the top cap, generically "hollow electrical conductor." may be electrically connected to an internal electrode other than an anode of a given device. Moreover, the means extending through the open end of the hollow electrical conductor for electrically connecting the internal electrode, e.g., anode, to the conductor may be other than the connector 32 and U-shaped conducting support wire 28 combination shown in H6. 1. A single member, such as a spring, attached to the electrode or not, may be employed, for example. Finally, various known equipment and techniques can be applied to the making of the novel device.

What is claimed is:

1. An electric discharge device comprising a closed envelope, an electrode within said envelope, a hollow metal conductor sealed through said envelope, said hollow conductor having a closed portion extending outside said envelope and an open portion extending within said envelope, and a metal connector fixed to said electrode and having a part extending into said open portion of said hollow conductor, said connector part comprising a plurality of resilient appendages press-fitted into said open conductor portion and in resilient contact with the inner wall of said hollow conductor.

2. The electron discharge device in accordance with claim 1, wherein said hollow conductor is tubular, said connector part forming an end portion of said connector, said appendages being integral with each other and having free ends extending from said connector end portion, said metal connector fixed to said electrode by at least two of said appendages being fixed at their free ends to said electrode. 

1. An electric discharge device comprising a closed envelope, an electrode within said envelope, a hollow metal conductor sealed through said envelope, said hollow conductor having a closed portion extending outside said envelope and an open portion extending within said envelope, and a metal connector fixed to said electrode and having a part extending into said open portion of said hollow conductor, said connector part comprising a plurality of resilient appendages press-fitted into said open conductor portion and in resilient contact with the inner wall of said hollow conductor.
 2. The electron discharge device in accordance with claim 1, wherein said hollow conductor is tubular, said connector part forming an end portion of said connector, said appendages being integral with each other and having free ends extending from said connector end portion, said metal connector fixed to said electrode by at least two of said appendages being fixed at their free ends to said electrode. 